Predicting Polyolefin Foamability Using Melt Rheology
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Transcript Predicting Polyolefin Foamability Using Melt Rheology
Predicting Polyolefin
Foamability Using
Melt Rheology
Associated Polymer Labs
Presented by Jim Zwynenburg
Agenda
Define
Rheology Test
Resulting Data
Converting Data
Plots
Interpretations
Examples
Remember to Remember
2
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Definitions
Rheology
Rheo means Flow
Ology means the
study of
Melt Strength
The Study of Flow
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Is a property of the
polymer melt which
indicates its ability
to withstand drawing
without breaking.
3
ASTM D-4440
Standard Test Method for Plastics: Dynamic Mechanical Properties Melt Rheology
Frequency Sweep at 190C
Temperature Ramp from
140C-230C for
Polyethylene
Temperature Ramp from
180C-260C for
Polypropylene
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Rheology Test Sensitivity Increases with
Decreasing Frequency
Tan delta verses Temp
3.5
3.0
C:\RSIOrche600\Data 2000\June\RSI Orchestrator Document.RSD
tan_delta
Tan delta v erses Temp
Westlake EF606, TR 100 rads, 200-130C
Westlake EF606, TR 10 rads, 200-130C
Westlake EF606, TR 1.0 rads, 200-130C
Westlake EF606, TR 0.1 rads, 200-130C
0.1 rads/sec
)
2.5
tan_delta (
[]
2.0
1.5
1.0 rads/sec
1.0
10 rads/sec
0.5
100 rads/sec
0.0
120.0
130.0
140.0
150.0
160.0
170.0
180.0
190.0
200.0
210.0
Tem p [°C]
ISO 6721-10
ASTM D4440-95a
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Rheology Lab for Solids and Melts
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Typical Data from Temperature Ramp
Temp (C)
Eta*
G' (Pa)
G" (Pa) Tan-delta (Pa-s)
139.7
16904
14605 0.86399
3557
144.0
16320
14210 0.87075
3446
149.5
15503
13740 0.88627
3299
154.9
14704
13290 0.90385
3156
160.0
13926
12875 0.92448
3020
165.4
170.1
175.0
180.0
185.4
190.1
195.0
200.4
205.0
210.1
215.5
220.0
225.1
230.5
13127
12405
11645
10909
10093
9427
8741
8005
7430
6823
6217
5757
5256
4773
12451
12046
11609
11188
10667
10242
9769
9241
8823
8343
7856
7465
7040
6603
0.94848
0.97107
0.99693
1.0255
1.0568
1.0864
1.1177
1.1545
1.1875
1.2229
1.2636
1.2967
1.3395
1.3833
2881
2754
2618
2488
2338
2217
2087
1947
1837
1716
1595
1501
1399
1297
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Rheology Plot 1
Best Low Density Polyethylene for Foam
10
5
10
Data: Eta*(Temp) [1..19] (19 pts)
Note: o = 4393.7
Model: Ellis Model
(c -1)
Eqn: c1/(1+(x/c 2) 3 )
Fit Error:
)
4
G' / G" Crossover Point:(175.58,1.156x10 )
0.9999
3 Coefficients:
4393.7
190.61
5.5729
Eta * (
[ Pa -s]
G"(
[ Pa ]
4
4
)
10
G' (
[ Pa ]
)
10
3
130.0
10
140.0
150.0
160.0
170.0
180.0
190.0
200.0
210.0
220.0
230.0
3
240.0
Temp [°C]
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Converted Data
Temp (C)
Eta*
Torque Phase
Log tan- Log Eta*
G' (Pa)
G" (Pa) Tan-delta (Pa-s)
(g/cm)
Angle
delta
(Pa-s)
139.7
16904
14605 0.86399
3557
67.162
40.827
-0.063
3.551
144.0
16320
14210 0.87075
3446
67.164
41.048
-0.060
3.537
149.5
15503
13740 0.88627
3299
67.167
41.55
-0.052
3.518
154.9
14704
13290 0.90385
3156
67.169
42.109
-0.044
3.499
160.0
13926
12875 0.92448
3020
67.172
42.753
-0.034
3.480
165.4
170.1
175.0
180.0
185.4
190.1
195.0
200.4
205.0
210.1
215.5
220.0
225.1
230.5
13127
12405
11645
10909
10093
9427
8741
8005
7430
6823
6217
5757
5256
4773
12451
12046
11609
11188
10667
10242
9769
9241
8823
8343
7856
7465
7040
6603
0.94848
0.97107
0.99693
1.0255
1.0568
1.0864
1.1177
1.1545
1.1875
1.2229
1.2636
1.2967
1.3395
1.3833
2881
2754
2618
2488
2338
2217
2087
1947
1837
1716
1595
1501
1399
1297
56.363
56.366
56.368
56.371
47.202
47.204
47.207
40.223
40.226
40.229
33.753
33.756
33.759
28.089
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43.485
44.159
44.912
45.722
46.583
47.372
48.18
49.101
49.899
50.725
51.642
52.362
53.256
54.136
-0.023
-0.013
-0.001
0.011
0.024
0.036
0.048
0.062
0.075
0.087
0.102
0.113
0.127
0.141
3.460
3.440
3.418
3.396
3.369
3.346
3.320
3.289
3.264
3.235
3.203
3.176
3.146
3.113
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Plotting Data
Tan-Delta (G”/G’)
Converted into log.
Fractions (less than
one, become negative
numbers)
Plot on Linear Scale
Eta* (Complex
Viscosity) converted
into log.
Decimal place
becomes the first
number, example
4000Pa-sec is 4.0
Plot on Linear Scale
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Rheology Plot 2
Log tan-delta
0.200
Log Tan-delta (G"/G')
Temp (C)
230
225
220
215
210
205
200
195
190
185
180
175
170
165
160
155
150
145
140
0.150
0.100
0.050
0.000
3.000
-0.050
3.100
3.200
3.300
3.400
3.500
3.600
-0.100
Log Viscosity (Eta*)
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Rheology Plot 3
Best Low Density Polyethylene for Foam
0.6
0.55
Low Melt Elasticity and Strength
Low Viscosity
High Density Foam Only
0.5
0.45
)
0.4
0.35
Log Tan -delta (
[ ( G "/ G ')]
0.3
0.25
Higher Temperature
Low er Viscosity
Low Melt Elasticity and No Strength
0.2
230C
0.15
Important Factors;
1) Slope
0.1
2) Length
3) Shape
0.05
0.0
-0.05
140C
-0.1
Low Temperature
Higher Viscosity
Greater Melt Elasticity and Strength
-0.15
Polystyrene Area
High Eleasiciaty and Melt Strength
High Viscosity
-0.2
2.8
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
4.6
4.8
Log Viscosity [ Pascal-sec]
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Rheology Plot 4
Polyolefin Foaming Window
1.0
LDPE
0.9
Low Melt Strength
0.8
LLDPE
)
0.7
Polypropylene
0.6
Log tan delta
[]
(
0.5
0.4
0.3
Branched LDPE
0.2
HMS PP
0.1
HDPE
PolyStyrene
0.0
High Melt Strength
-0.1
Every
Polyolefin has
a Unique
Curve
Fingerprint The
Resin
Know the
response of the
polymer
Imagine The
Possibilities
-0.2
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Log Eta* [ ]
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Example 1, Using Recycled Resin
4 PCF Foam
0.6
0.55
Log Tan-delta
4 PCF Foam
4 PCF Foam with Recycled Resin
0.5
0.45
)
0.4
0.35
Log Tan -delta (
[ ( G "/ G ')]
0.3
0.25
Recycled
content
appears to
separate at
higher
temperatures
0.2
0.15
0.1
0.05
0.0
-0.05
-0.1
-0.15
-0.2
2.8
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
4.6
4.8
Log Viscosity [ Pascal-sec]
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Example 2, Blending Vertically
Blending Polymers; Equistar NA957, NA940, 75/25 Blend
0.6
0.55
Blending Rule
1+2=3
0.5
0.45
)
0.4
0.35
Log Tan -delta (
[ ( G "/ G ')]
0.3
0.25
0.2
Equistar NA 957
0.15
0.1
0.05
Blend 75%/25%
0.0
-0.05
Fractional Melt
Equistar NA 940
-0.1
To blend
Polyolefins,
Use the WZ
Theorem:
geometric
averaging of
the viscosities
produces the
new blended
viscosity.
-0.15
-0.2
2.8
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
4.6
4.8
Log Viscosity [ Pascal-sec]
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Example 3; Blending is as easy as 1,2,3
0.6
Log tan delta
LDPE 25% LLDPE 75%
0.4667
LLDPE Mix
LDPE 75% LLDPE 25%
LDPE 50% LLDPE 50%
Reprocessed LDPE
)
Virgin LDPE
0.3333
Log tan delta
[]
(
LLDPE Mix ed (Post Industrial)
Pellets
0.2
25% / 75%
1
0.06667
Virgin LDPE
50% / 50%
75% / 25%
Reprocessed LDPE
-0.06667
-0.2
2.9
Hidden Information
3.1
3.3
3.5
3.7
3.9
Log Eta* [Pa-s]
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Remember to Remember
Polyolefins viscosity is 1+2=3
Testing takes one hour
Measure and Know the Resin Properties
Applies to recycled, fractional melts, additives,
rheology modifiers, crosslinking agents, etc
New Models are available for all thermoplastic
materials
Cost Savings
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The End
I’m Grateful to share my experience and knowledge
Extra Special Thanks to Gary Wilkes
Special Thanks to Stephen Driscolle, University of
Massachusetts
Jay Patel, Patel Scientific
Members of the Foams Committee for accepting my paper
Everyone present for listening
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